In recent years, building construction techniques have experienced a rapid transition from traditional "stick" building to less labor intensive methods. Among these newer developments, "panelization" has emerged as one of the more promising building construction methods. This success is due primarily to two attributes of panelized building systems: (1) opportunity for extensive customization; and (2) substantially reduced construction time as evidenced by erection of a weathertight shell in a week or less. Residential and commercial customers alike continue to find this combination extremely desirable.
Accompanying the favorable aspects of panelization is an ongoing problem. While panels can be fabricated in endless variety to very exacting specifications, this is rarely the case for site built concrete or masonry building foundations. "Stick" builders have long been accustomed to contending with foundations constructed to inaccurate dimensions, out of plumb, level, and/or square in any variety of degrees and combinations. Due to a lack of adequate controls, every site constructed concrete or masonry building foundation will sustain one or all of these inconsistencies to some degree. This condition is expected to continue for the foreseeable future.
For panelizers who wish to build rapidly and repetitively to ideal sizes, this is a serious and potentially expensive problem. Even slight discrepancies result in enormous cost overruns due to the increased number of man-hours required to "adjust" prefabricated panels and/or existing building foundations.
In 1985, approximately 25 to 35 percent of all homes built were to some degree erected by the home owner or the home owner acting as a general contractor. Many of these homes included prefabricated wall panels to reduce the cost of construction. Typically, prefabricated wall panels appeal to the first time home owner, retirees and the home owner with the need for additional space. Affordable housing is thereby made available without compromising quality, style and thermal efficiency.
An example of a prefabricated wall panel is disclosed in U.S. Pat. No. 3,665,662 to Timbrook et al. In this patent a structural member is made of a rectangular rigid core of 35/8 inch thick expanded resin impregnated honeycomb kraft paper. Glued on both sides of the core is a one-half inch thick board. The core is recessed from one lateral edge and projects from an opposite lateral edge. Horizontal channels are formed by the recessed top and bottom surfaces of the core.
Adjacent structural members interlock with each other and rest upon a sole plate which is supported by a foundation. The location for receptacles, switches and fixtures are marked on the interior panel. The panel is then cut to permit the insertion of the receptacles, switches and fixtures therein at the cut-out location. Conduit is extended through the honeycomb core to make suitable connections to the receptacles, switches and fixtures.
Another example of a prefabricated wall panel is a prior commercial panel referred to generally in the literature as a "stress skin" panel.